1. Technical Field
The invention relates generally to the field of hand tools. More specifically, the invention is directed to an improved locking clamp device suitable for use with difficult work pieces and environments.
2. Description of Prior Art
Locking clamps are well-known in the art. Vise-Grip™ brand locking pliers are an example. Such clamps include a handle mechanism, a clamping mechanism manipulated by the handle mechanism, and a locking mechanism suitable for retaining the clamping mechanism in a fixed position relative to a work piece. There many different known methods for implementing these basic structures, for which myriad patents have been issued. The great majority of these prior patents involve various improvements or modifications to the locking mechanisms. See Kramer, U.S. Pat. No. 6,601,479 (Aug. 5, 2003), SELF ADJUSTING LOCKING PLIERS, disclosing one-handed locking pliers; Wrigley, et al., U.S. Pat. No. 6,199,458 (Mar. 13, 2001), LOCKING PLIERS, disclosing locking pliers with internal springs to provide tension and a thumb catch for locking/unlocking the tool. Other patents disclose mechanisms for adjusting the angle of the jaws of the clamping mechanisms to accommodate different sizes of work pieces to be gripped. See Whiteford, U.S. Pat. No. 6,408,724 (Jun. 25, 2002), SELF ADJUSTING PLIER-LIKE LOCKING TOOL, disclosing locking tool adjustable to different sized work pieces. Other patents involve tools having jaws which move in relation to the handle mechanisms. See Troudt, U.S. Pat. No. 6,708,966 (Mar. 23, 2004), ADJUSTABLE C-CLAMP, disclosing clamping mechanism with telescoping functionality to widen the distance between the jaws; Chou, U.S. Patent Application No. 2003/0015072 (Jan. 23, 2003), VARIABLE PIVOT LOCKING PLIERS, disclosing locking pliers having parallel jaws; Chou, U.S. Patent Application No. 2002/0157507 (Oct. 31, 2002), AUTOMATIC AND VARIABLE GRIP LOCKING PLIERS, disclosing locking pliers that will automatically reset the jaws to accommodate different sized work pieces; Galea, U.S. Pat. No. 5,992,273 (Nov. 30, 1999), ADJUSTABLE LOCKING PLIERS, disclosing a tool with pivotally mounted jaws which move relative to the handle.
Other patents are closer in concept to the present invention, though remain distinguishable. Stahle, U.S. Pat. No. 6,308,597 (Oct. 30, 2001), for LOCKING DEVICE FOR A HAND TOOL, discloses a locking clamp having interchangeable clamping surfaces in the form of collet jaws. These are described as having a rib which fits into a channel formed into the end of the jaw of the clamp; the various collet jaws may be slid into and out of the channel to quickly change the function of the clamp. The collect jaws may also pivot. This differs from the present invention in that the collet jaws are not variously shaped or contoured to accommodate different work piece surfaces, they cannot be rotated relative to the jaws, and they cannot be used to simulate spot welding marks. Moreover, Stahle does not disclose extendable jaws. Bogert, et al., U.S. Pat. No. 4,896,661 (Jan. 30, 1990), for MULTI PURPOSE ORTHOPEDIC RATCHETING FORCEPS, discloses locking surgical forceps having readily interchangeable tips, said tips able to be rotated along the axis of the arm. However, the clamping tips cannot pivot and are not resilient or contoured, and the jaws are not extendable. Hopper, et al., U.S. Pat. No. 6,860,179 (Mar. 1, 2005), for CLAMP DEVICE, discloses clamping surfaces which may be removed from the jaws. These removable clamping surfaces are designed as wear items and are not intended to be interchanged with different clamping surfaces during use to accommodate different work pieces. Hopper, et al., does not teach the use of differently shaped clamping surfaces, variable materials for clamping surfaces, or the concept of positional clamping surfaces. Reiter, U.S. Pat. No. 3,779,108 (Dec. 18, 1973), for CLAMP, discloses a variation of a spring clamp, with gripping surfaces pivoting in one dimension and with the arms of the jaws themselves rotating. The Reiter clamp also discloses resilient pads covering the clamping surfaces. These are not interchangeable, however, nor are the clamping surfaces of diverse shapes. Finally, the Reiter clamp discloses extendable arms, but the extension is lateral, perpendicular to the handles, thereby only providing for a wider grip, and not for extending axially from the handles. Barbosa, U.S. Pat. No. 6,290,219 (Sep. 18, 2001), C-CLAMP PLIER WITH SUPPORT EXTENSION ARM, discloses an extendable arm attachment to be used in combination with a clamp. It is distinct from the telescoping extendable jaws concept of the present invention in that it has an independent extension arm to be placed on an existing jaw of the clamp, plus a counter-pressure point below the jaw.
Other patents disclose individual concepts similar to the present invention, but represent inferior solutions. Swanstrom, Jr., U.S. Pat. No. 6,748,830 (Jun. 15, 2004), for THREADED GRIPPING BAR PLIERS INSERT, discloses replaceable clamping surfaces. However, these clamping surfaces are replaced only as wear items, are fixed when in use, and are not intended for quick release or interchangeability during use. Domenge, U.S. Pat. No. 6,401,578 (Jun. 11, 2002) and U.S. Pat. No. 6,389,936 (May 21, 2002), for HAND TOOL HAVING PIVOTING HANDLES, disclose pliers with pivoting contact elements on the jaws. These are fixed onto the jaws, and designed to grip only six-sided fasteners. Tally, U.S. Pat. No. 6,134,993 (Oct. 24, 2000), for PLIERS WITH ADJUSTABLE JAWS, discloses pliers with jaws that may be oriented in various positions relative to the handles. This patent discloses soft clamping surfaces, though these are in fact simply vinyl jaw covers placed over the gripping surfaces to protect the work piece. They are not designed to be readily interchanged for use with different types of work pieces. Wolff, et al., U.S. Pat. No. 5,791,210 (Aug. 11, 1998), for SPRING-TENSIONING PLIERS, discloses pivoting clamping surfaces, similar to the pivoting clamping surfaces disclosed in Reiter. However, the clamping surfaces are not interchangeable and pivot in one dimension only. Shin, et al., U.S. Pat. No. 4,133,519 (Jan. 9, 1979), for VISE WITH SELECTABLE JAW FACES, discloses the use of interchangeable clamping surfaces to be used with different types of work pieces. However, the mechanism for changing the clamping surfaces is a disk which is rotated to position the desired clamping surface for use. This is limited to just a few different clamping surfaces. Moreover, the mechanism is not suitable for use in a hand tool.
None of the disclosed prior art offers all of the functionality disclosed in the present invention. Moreover, the implementation of similar individual concepts in earlier patents differs significantly with the implementation of the present invention. Thus none of the disclosed prior art anticipates the present invention.
It is an objective of the present invention to provide a useful, improved locking clamp device with independently extendable jaws to provide for improved access to difficultly situated work pieces and for offset clamping.
It is a further objective of the present invention to provide a useful, improved locking clamp device with quick release interchangeable clamping members.
It is a further objective of the present invention to provide a useful, improved locking clamp device with clamping members moveable relative to the jaws to better accommodate work pieces.
It is a further objective of the present invention to provide a useful, improved locking clamp device with variously shaped clamping members suitable for use with difficultly situated work pieces.
It is a further objective of the present invention to provide a useful, improved locking clamp device suitable for creating simulated spot welds in metal work pieces.
Other objectives of the present invention will be readily apparent from the descriptions that follows.